The present invention relates to an elevator installation for conveying persons/goods, a method of operating the elevator installation and a method of modernizing an elevator installation.
In the case of new installations of elevators, the desire exists for space-saving elevator installations which are simple to install. This has the consequence that the elevator installations no longer require separate engine rooms, but fit in simply conceived, standardized parallelepipedonal shafts. The costs in planning and construction of the building are thus reduced and the usable building space increases.
In the case of modernizations of elevator installations, the desire exists for an increase in the conveying capacity of the elevator installations. This increase in performance, however, is to be realized with small constructional changes to the building in order to keep down the costs of modernization.
U.S. Pat. No. 5,419,414 shows an elevator installation with several cages arranged one above another in a shaft. The cages are moved independently of one another. Each cage has a drive and a counterweight. The cages are connected with counterweights by way of cables as conveying means. In order that all cages can serve the same storeys of the building, diversion spaces are provided above and below the storeys served by the cages. Thus, first cages can move in these diversion spaces and further cages can move to the place in the shaft of the first cages. The drives are mounted above the shaft. This elevator installation achieves an increase in conveying performance by increasing the number of cages in the shaft.
A disadvantage of the teaching according to U.S. Pat. No. 5,419,414 is that the mounting of several drives in an engine room above the shaft is costly. Such an engine room is often difficult with respect to access. For example, the drives have to be broken down for transport into the engine room, so that they can pass through passageways and doors, which passageways and doors lie on the route to the engine room. In addition, it is disadvantageous that the presence of an engine room above the shaft as well as the provision of passing places in the shaft keeps down the potential usable building space. In particular, storeys which are disposed at the level of the passing spaces might not be served by the cages. It follows from these disadvantages that new installation and modernization of such an elevator installation causes high costs.